Substituted β-benzyl-γ-butyrolactones are known for their biological properties such as anticancer activities and they are also the key intermediates in the synthesis of butyrolactone lignans as well as other natural products. Due to various pharmacological and medicinal properties associated with butyrolactones and related lignans, the chemical synthesis of the intermediate butyrolactones has been the major target of several synthetic schemes. One of the more common synthetic strategies utilizes Stobbes condensation of an aromatic aldehyde with alkyl succinates followed by selective reduction (Banerji, J., Biswanath, D. Heterocycles, 1985, 23(3), 661–5 (b) Shao, L., Miyato, S., Muramatsui, H., Kawano, H., Ishi, Y., Soburi, M., Uchida, Y. J. Chem. Soc. Perkin Trans. (I), 1990, 5, 1441–5 (c) Marimoto, T., Chiba, M., Achiwa, K. Tetrahedron, 1993, 49(9), 1793–806). Besides several novel synthetic methodologies have also been reported for the asymmetrisation of the butyrolactones and the lignans[(a) Vanderlei, J. M. de. L., Coelho, F. and Almeida, W. P. Synth. Comm. 1998, 28(16), 3047–55. (b) Canton, J. L. Can. J. Chem. 1997, 75(8), 1076–83. (c) Filho, H. C. A., Filho, U. F. L., Pinheiro, S., Vasconcells, M. L. L. A., Costa, P. R. R. Tetrahedron Asymm. 1994, 5(7), 1219–20 9 (d) Costo Paulo, R. R. V. Ferreiro J. Braz. Chem Soc., 1996, 7(1), 67–73. Chem. Abstr. I24:26068Iy].
In recent years asymmetric syntheses of optically active butyrolactones and corresponding lignans have also been achieved using the chemo-enzymatic methods [(a) Vanderlei, I. M. de. L., Coelho, F. and Almeida, W. P. Synth. Comm. 1998, 28(16), 3047–55. (b) Caniton, J. L. Can. J. Chem. 1997, 75(8), 1076–83. (c) Filho, H. C. A., Filho, U. F. L., Pinheiro, S., Vasconcells, M. L. L. A., Costa, P. R. R. Tetrahedron Asymm. 1994, 5(7), 1219–20 9 (d) Costo Paulo, R. R. V. Ferreiro J. Braz. Chem Soc., 1996, 7(1), 67–73. Chem. Abstr. 124:260681y].
Most of the known processes or synthesis of substituted β-benzyl-γ-butyrolactones are either inconvenient to carry out on higher scale because of the complexity of the reactions or due to the unavailability of the starting materials. These methods also suffer from low over all yields. They also involve complex experimental conditions, which are lacking reproducibility.